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721.
722.
Understanding the technical requirements and underlying biomechanics of complex release and re-grasp skills on high bar allows coaches and scientists to develop safe and effective training programmes. The aim of this study was to examine the differences in the functional phases between the Tkatchev and Kovacs skills and to explain how the angular momentum demands are addressed. Images of 18 gymnasts performing 10 Tkatchevs and 8 Kovacs at the Olympic Games were recorded (50 Hz), digitised and reconstructed (3D Direct Linear Transformation). Orientation of the functional phase action, defined by the rapid flexion to extension of the shoulders and extension to flexion of the hips as the performer passed through the lower vertical, along with shoulder and hip angular kinematics, angular momentum and key release parameters (body angle, mass centre velocity and angular momentum about the mass centre and bar) were compared between skills. Expected differences in the release parameters of angle, angular momentum and velocity were observed and the specific mechanical requirement of each skill were highlighted. Whilst there were no differences in joint kinematics, hip and shoulder functional phase were significantly earlier in the circle for the Tkatchev. These findings highlight the importance of the orientation of the functional phase in the preceding giant swing and provide coaches with further understanding of the critical timing in this key phase.  相似文献   
723.
Rats searched for food hidden on top of poles in a 4 × 4 matrix of poles. Before each trial, the location of the four baited poles was unpredictable. However, the poles were always baited in one of two spatial patterns, either a square or a line. The food hidden on the four baited poles was one of two types, and the food type determined the identity of the pattern. Thus, once one baited pole was discovered, the food type provided a cue for the spatial pattern in which the remaining food was hidden. The results showed that rats learned the two spatial patterns in which the food was hidden and used the conditional cue to determine which pattern was relevant on individual trials, thereby increasing the efficiency of spatial search.  相似文献   
724.
This study evaluates the impact of an independent postmidterm question analysis exercise on the ability of students to answer subsequent exam questions on the same topics. It was conducted in three sections (~400 students/section) of introductory biology. Graded midterms were returned electronically, and each student was assigned a subset of questions answered incorrectly by more than 40% of the class to analyze as homework. The majority of questions were at Bloom's application/analysis level; this exercise therefore emphasized learning at these higher levels of cognition. Students in each section answered final exam questions matched by topic to all homework questions, providing a within-class control group for each question. The percentage of students who correctly answered the matched final exam question was significantly higher (p < 0.05) in the Topic Analysis versus Control Analysis group for seven of 19 questions. We identified two factors that influenced activity effectiveness: 1) similarity in topic emphasis of the midterm-final exam question pair and 2) quality of the completed analysis homework. Our data suggest that this easy-to-implement exercise will be useful in large-enrollment classes to help students develop self-regulated learning skills. Additional strategies to help introductory students gain a broader understanding of topic areas are discussed.  相似文献   
725.
Psychological models of learning have been shaped by information processing models for four decades. These models have led to teaching models based on information transfer from teachers to students. However, recent research in many fields shows that information processing models do not account for much of human competence in everyday scientific and lay contexts. At the same time, situated cognition models have been developed that better account for competence in widely differing situations. The implications of situated cognition are rather different from those of information processing. Teaching and learning are no longer conceived simply in terms of information transfer but as increasing participation in everyday practices. Conceiving of science learning as a trajectory of increasing participation asks educators to rethink the purpose of science education from preparing scientists to preparing citizens to participate in public enactments of science, and this entails deinstitutionalising school science to take science beyond the classroom walls.  相似文献   
726.
Objective: To explore the prevalence of, characteristics of, and factors associated with forgetting of childhood sexual abuse memories in a large non-clinical sample (N = 1712).Method: Using an anonymous survey, we asked respondents about (a) the nature and severity of their childhood abuse; (b) the continuity of their abuse memories; and (c) their experiences with others suggesting to them that they might have been abused.Results: A substantial minority of victims in our sample reported having temporarily forgotten their childhood sexual abuse. Forgetting was largely unassociated with victim or abuse characteristics. Compared to individuals who always remembered their abuse, however, individuals who temporarily forgot were more likely to report that someone had suggested to them that they might have experienced abuse. Those who received such suggestions were particularly likely to suspect that they may have experienced childhood sexual abuse that they do not yet remember.Conclusion: Forgetting may be less common than implied by earlier estimates from clinical samples, yet it is not uncommon. Also, a sizable minority of the population is wondering whether they have experienced unremembered abuse, and these suspicions are linked to having encountered suggestions from others. We discuss the implications of these findings for understanding the phenomenon sometimes labeled repression.Spanish abstract was not available at time of publication.  相似文献   
727.
The purpose of this study was to compare the motor skill performance of preschool children from low socioeconomic (SES) backgrounds to their age matched typically developing peers using the Peabody Developmental Motor Scales-2 (PDMS-2). Sixty-eight children (34 low SES and 34 typically developing; ages 3–5) performed the PDMS-2. Standard scores from each subtest (i.e., stationary, locomotion, object manipulation, grasping, and visual-motor integration) and three quotient scores were calculated for the children identified as low SES and typically developing children. A MANOVA was used to analyze the PDMS-2 standard score and quotient score differences between the children identified as low SES and the typically developing children. All preschool children identified as low SES scored at average or lower on total motor quotient scores. Specifically, 88.2 % of children identified as low SES were classified as average, and 11.8 % of children were in the below average performance category. The MANOVA analysis showed that children identified as low SES scored significantly lower than the typically developing children on the visual-motor integration subtest, F(1,64) = 7.232, p = .009; locomotion subtest, F(1,64) = 11.449, p = .001; and TMQ, F(1,64) = 4.732, p = .033. Children identified as low SES were significantly delayed in both fine and gross motor skill areas when compared to their typically developing age and gender matched peers. Researchers are recommended to provide comprehensive assessments for preschool children and to include motor tasks when designing early intervention programs.  相似文献   
728.
In recent years, Western governments have come under sharp criticism for their use of surveillance technology. They have been accused of sweeping up massive amounts of information without evidence of the technologies being effective in improving security. The view of critics is clear, but what do intelligence officials themselves say? This paper analyzes statements of intelligence officials in the U.S. and U.K. from 2006 to 2016, examines what criteria officials use in their discourse on effectiveness, and investigates how considerations of cost and proportionality factor into the equation. It identifies seven measures of effectiveness in the statements of intelligence officials, and finds that cost, though rarely discussed, is the driver behind formalized evaluations of surveillance programs.  相似文献   
729.
Rowers need to combine high sprint and endurance capacities. Muscle morphology largely explains muscle power generating capacity, however, little is known on how muscle morphology relates to rowing performance measures. The aim was to determine how muscle morphology of the vastus lateralis relates to rowing ergometer performance, sprint and endurance capacity of Olympic rowers. Eighteen rowers (12♂, 6♀, who competed at 2016 Olympics) performed an incremental rowing test to obtain maximal oxygen consumption, reflecting endurance capacity. Sprint capacity was assessed by Wingate cycling peak power. M. vastus lateralis morphology (volume, physiological cross-sectional area, fascicle length and pennation angle) was derived from 3-dimensional ultrasound imaging. Thirteen rowers (7♂, 6♀) completed a 2000-m rowing ergometer time trial. Muscle volume largely explained variance in 2000-m rowing performance (R2 = 0.85), maximal oxygen consumption (R2 = 0.65), and Wingate peak power (R2 = 0.82). When normalized for differences in body size, maximal oxygen consumption and Wingate peak power were negatively related in males (r = ?0.94). Fascicle length, not physiological cross-sectional area, attributed to normalized peak power. In conclusion, vastus lateralis volume largely explains variance in rowing ergometer performance, sprint and endurance capacity. For a high normalized sprint capacity, athletes may benefit from long fascicles rather than a large physiological cross-sectional area.  相似文献   
730.
We develop and test a dual-route model of genetic effects on reading aloud and spelling, based on irregular and non-word reading and spelling performance assessed in 1382 monozygotic and dizygotic twins. As in earlier research, most of the variance in reading was due to genetic effects. However, there were three more specific conclusions: the first was that most of the genetic effect is common to both regular and irregular reading. In addition to this common variance evidence was found for distinct genes influencing the acquisition of a lexicon of stored words, and additional genetic effects influencing the acquisition of grapheme–phoneme correspondence rules. The third conclusion, from a combined model of reading and spelling, is that reading and spelling have a common genetic basis. Models that did not distinguish lexical and non-lexical performance fit significantly worse than dual route genetic models. An implication of the research is that models of reading, whether connectionist or dual-route, must allow for the genetic independence of neurological processes underlying the decoding of non-words and irregular words.  相似文献   
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